Super-fit participants in the National Senior Games show a fitness age up to 25 years younger than their chronological age thanks to their cardiovascular health, says a U.S. doctor who took to Facebook with the findings to inspire people of all abilities.

Dr. Pamela Peeke, an assistant professor of medicine at the University of Maryland who started running at age 40, is a triathlete involved in the Games, which start Friday in Minnesota.

Fellow researcher Ulrik Wisloff at the Norwegian University of Science and Technology in Trondheim designed the calculator and has published research based on findings in Norwegians. When Peeke learned of the calculator, she jumped at the opportunity to collaborate with Wisloff on another group: competitors at the National Senior Games.

The online calculator asks people to provide information such as their age, city, ethnicity, how often they work out and how hard, as well as resting and maximum heart rates to estimate cardiovascular fitness level or "fitness age."

The average age of the Senior Games participants was 68. Their average fitness age was 43, Peeke said on Facebook after the findings were featured in the New York Times. 

The pair wanted to "get the word out on the fitness age immediately because that was sort of astounding that you can clip off a quarter century by putting yourself in that kind of condition," Peeke said in an interview Thursday.

"This is striking data."

Assume the vertical

Peeke invites people to use the calculator as motivation. Unlike standard lab measurements like cholesterol or blood sugar levels, the fitness age tells you how you perform, she said, like how you feel walking up a flight of stairs or running after a child.

"What if I told you that you could make your fitness age five years younger? Hey grab it. The good news is you can always change your fitness age," Peeke advised. "You don't have do anything more than just get up and walk. Assume the vertical and don't stop moving."

When one woman commented that she felt hopeless that her fitness age was higher than her real age, Peeke replied it's the perfect time to reverse it.

Peeke said many of the Senior Games' participants are like her and took up competing in their 40s and 50s when family and work obligations eased enough to "crow bar" the intense training into their lives. 

As members of the American College of Sports Medicine, Peeke and Wisloff plan to parse the data from Senior Games participants over the next few weeks to explore differences between men and women and various sports.

So far, men and women seem to be neck and neck, Peeke said, but they're hoping for more data. They aim to publish those findings in 2016.